V8 Rebuild

The story of the rebuild of Andymadmak’s TVR400SE engine and gearbox

I’m not sure exactly when it happened. It could have been at warp factor 15 on the peage south of Paris that day in mid June or perhaps it was a couple of days later as I was pounding down the Mulsanne straight, riding a tidal wave of wedge noise and soaking up the sun.

Either way, at some point in the proceedings my beloved TVR 400se started to feel a little tired. Nothing I could point a finger at mind you. Still started first time, idled well enough and pulled smoothly. But it was as if the Beast’s heart wasn’t quite in it any more.

It didn’t initially seem too serious though. In the face of imminent Porsche Boxster attack I could still call down to the engine room for maximum revolutions, safe in the knowledge that I’d get sufficient ferocity to deal with the Hun threat, but the delivery seemed a touch sleepy, and dare I say it of a big wedge, a little soft!?

The killer punch came a couple of months later when I stopped to talk to a friend. “What’s wrong with the car?” he asked. “ It seems awfully quiet compared to normal”
He was right of course, I’d been deluding myself into thinking there was no problem and here was the evidence that others had noticed the beast’s decline. Something had to be done about it.

We shall Rebuild it!

Having toyed briefly with the idea of a completely new engine from any one of the myriad of “We build very powerful Rover V8s” specialists, I finally decided that I wanted to keep my wedge close to the original spec, so I plumped for a full engine rebuild complete with those small but essential improvements where financially feasible.

But who should I get to to do it? After much agonising and phoning round, but still not having made a choice, I realised I needed help with the decision. I contacted Mike Johnson at Boost Performance in Nottingham (known on Pistonheads as Boosted LS1) and sought his views on the subject.

Through PistonHeads, I had helped Mike with some marketing advice for his business earlier in the year – Mike custom builds fabulous Chevrolet LS1 engines for those with the money and a desire to go at warp nine with Yankee reliability. Of course, he manages to include a few little self designed and engineered extras that help make them even more powerful than General Motors imagined. You want it turbocharged sir? No problem, one turbine or two? I thought he’d be a good guy to tell me who to chose for my own little TVR fettling project (an LS1 won’t fit into a wedge without some major fettling!) .

Needs & Wants

Mike wanted to know precisely what I had noticed different about the engine, what I had liked and disliked about the unit when it was in good health and what I wanted to get from the rebuild. The more we chatted, the more I liked his approach to engine building, which is based on precision measurements, engineering and mechanical optimisation rather than electronics and peripheral gubbins.

In the end, to my delight Mike offered to do the rebuild for me, and at a price that was no worse than any of the other quotes I’d had. The only caveats were that I wasn’t allowed to rush him (he’s very busy) and that he be allowed to do it his way!

I delivered the beast to Mike’s Nottingham workshop on the 1st November and as I was leaving he handed me a fat wodge of computer print outs for me to study.
Mike has a neat computer programme that enables him to simulate the final spec of any engine he’s working on. In theory, this makes things like camshaft selection a lot simpler! The papers he handed me were Torque and BHP curves for a dozen different camshaft profiles that he’d run off for me to consider, using the basic information he already had on the engine. He told me to ignore the specific figures as it was likely that they would change once he’d inputted the actual measurements from my engine. They would however give me a good feel for what was out there.

In the weeks that followed Mike sent me more cam profile graphs as he worked his way down through the unit, taking measurements as he went and inputting them to the programme.

It became very clear very quickly that the engine had never been producing TVRs much quoted 270bhp for the unit. Whilst the heads were very nicely ported and polished the (standard Rover) pistons were running way down the bores.

Mike calculated that the static compression ratio was no better than 8.8 : 1 (TVR claim 10.5:1) and there was so much blow by on the rings that it’s probable that the unit was closer to 200bhp than 270! I got quite depressed but Mike told me not to worry. “I can make it better, just trust me” he said.

'Boxing

Well it was too late not to now, so whilst I was trusting him I decided to ask him about rebuilding the gearbox too! It had been making some chattering noises under load and I figured that with the engine moved out of the way and Christmas coming up, now was as good a time as any to sell one of my children in order to get the ‘box done.
Mike immediately referred me to a man called Ken Tomlinson, whom he called a genius with gearboxes. He also warned me that Ken was a hard man to contact!

It proved to be so. Nearly two weeks went by before Ken returned my calls, and a meeting was arranged one night at Kens tiny workshop in Over Whitacre near Nuneaton. It was worth the wait. Tomlinson is semi retired now, but he has spent a lifetime in engineering, starting with Armstrong Siddeley, Rolls Royce and then more than 30 years at Standard Triumph/Rover. Kens workshop is an Aladdin’s cave of old parts gearboxes and axles from various Triumph, Jaguar and other racing cars of the past 40 years. For a man that’s retired, he seems awfully busy keeping lots of people on the track in their old racing and rally cars!

“Mind your head” is the oft repeated mantra as you enter the unit through a very low doorway, but I wouldn’t have minded if I had cracked my head. I love places like this which ooze history and engineering and craftsmanship. I could see why Mike recommended him. What Ken doesn’t know about gearboxes and axles probably isn’t worth knowing!

So I asked Ken if he knew much about the gearbox in the TVR (which is basically a Rover 5 speed unit) and he chuckled as he said he should do – he helped to design it!
For the next hour Ken kept me entranced with stories of how the early designs were decided upon, the challenges they faced, how the decision was made to use ATF fluid in the box in place of the more usual EP80 gear oil, and even how that decision was tested using the Solihull works canteen ladies one morning! Fantastic stuff!

I left the box knowing it couldn’t be in better hands, and with Ken’s advice ringing in my ears to locate some decent 75 gear oil to use in place of the “bloody awful” ATF fluid following the rebuild.

Homework

For the next week or so I studied cam profiles and print outs. Mike kept me updated on his further discoveries in the engine – cam was a bit worn, all bearings worn, crank good, but main bearings had been chattering, PAS pump knackered etc etc.

Mike suggested I should order some special gapless piston rings from the USA.
He felt they would really suit the engine and improve the low end efficiency by drawing more vacuum. The Arizona based manufacturer claims less than 1% blow-by, and judging by the state of my block internals I had been suffering a lot more than this prior to rebuild! Mike sent the block off to have 35 thou skimmed off the deck in an effort to get the compression ratio back to something a little more respectable, and he also had the bores re-honed and the whole lot chemically cleaned. The intake manifold was also skimmed so that it would match up to the ports properly.

There was some evidence of main bearing chatter and to stop this in future he suggested a stud kit in place of the normal bolts.

I still hadn’t chosen a camshaft though. Mike was adamant he would not choose it for me. “You know how you want to drive the car, use the graphs to choose a power distribution most in tune with how you drive” he said. The original unit had been a Kent 214, and I wanted something a bit beefier than that without going too mad!

In the end it came down to a choice between an Isky 282, a Kent 216 or a Kent 218 hybrid of some sort. Following some tips from fellow PHers, Tim Lamont at ACT and some communication with Shaun at V8 Developments, I finally chose a V8 Developments MC1 – which is a 218 hybrid. Shaun was excellent to deal with. He was really very helpful and knowledgeable, and in the final analysis this tipped the decision in favour of V8Dev. Mike was also happy – he rates V8Dev too!

'Box Done

At the end of November Ken called to say my gearbox was finished. It had needed new bearings, seals, breather and a bit of general fettling. When I went to collect it they had even repainted it! All for the unbelievably low cost of less than £250!

The sad thing is that in all likelihood he will have done such a good job that I probably won’t get to use him again before he finally does retire completely.

With all the bits finally in place the reassembly started on the 3rd December, but then tragedy struck. Mike broke his hand! It made any kind of heavy work an absolute agony for him. “Sorry Andy, it’s going to be the new year before it comes back!”

He did invite me over to see where he was up to with it though, and then promptly handed me several large lumps of metal, including the engine mounts, some peripheral castings and the rocker covers and told me to get them cleaning and (the mounts) repainted whilst I waited!

In fact Mike wasn’t able to start work on it again properly till early January, with a new target completion date set for early February. The problems weren’t over yet though. Halfway through putting the second cylinder head back on and a head bolt snapped! Mike was adamant, he said it was too risky to assume this would be an isolated problem and that I needed new head bolts all round. That meant taking the first head off again and replacing both gaskets again!

Fire her up!

In mid January Mike phoned. “Listen to this!” he yelled, and over the mobile I heard the sound of my mighty wedge exploding into life. It sounded fantastic and really brought a lump to my throat. I had to go over to see it the next day!

There was a still lot to be done, but the engine was back in. Mike started it for me and the hairs on the back of my neck stood up! The familiar deep growl was still there, but now there were new, harder, snarling tones overlaid too. I couldn’t wait to get it back on the road.

That day finally came on the 15th February when I went to collect the car (It had been ready on the 1st February, but I had been away).

Aside from some minor clutch and exhaust routing issues (both sorted within a couple of hours) everything was fine and the car felt awesome. Mike had even washed it for me!
First impressions? Well it’s still very tight, but it’s definitely much stronger and smoother in the mid range. It’s running a bit rich, and the stepper motor needs adjusting a bit but otherwise it’s problem free. The gearbox feels lovely too.